Usually, plants and mines which dangers might occur in operation will be equipped with certain amounts of real-time working condition alarm systems, in order to detect dangerous conditions and alarm in time, thus to guarantee the life and safety of workers.
In prior art, fixed or handheld detectors are assumed to detect dangerous conditions (such as dangerous gas, high pressure environment, high temperature environment etc.), when danger occurs, the detector will sent an alarm signal to a remote control centre, then the control centre will send an alarm, for example, the control centre may warning workers through ringing bells, initiating warning lamps and other means, thus the workers may evacuate in time.
It can seen that, in the prior art real-time working condition alarm system, the control centre is situated at the central position, when dangers are detected, the one which get the alarm signal first is control centre, thus the workers will be evacuated only after receiving the alarm from control centre. If the control centre failures or the reaction speed is too slow, it will badly affect the evacuation as well as the life and safety of workers. In addition, bells, warning lamps and other devices used to indicate alarm from control centre are usually disposed at a specific position in the plants, the workers who are closer to the position may quickly alerted to evacuate in time, but the worker who far away from the position might not be able to evacuate because of not receiving the alarm in time.